LXR linux/arch/mips/loongson64/loongson-3/cop2-ex.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 2014 Lemote Corporation.
   7 *   written by Huacai Chen <chenhc@lemote.com>
   8 *
   9 * based on arch/mips/cavium-octeon/cpu.c
  10 * Copyright (C) 2009 Wind River Systems,
  11 *   written by Ralf Baechle <ralf@linux-mips.org>
  12 */
  13#include <linux/init.h>
  14#include <linux/sched.h>
  15#include <linux/notifier.h>
  16
  17#include <asm/fpu.h>
  18#include <asm/cop2.h>
  19#include <asm/current.h>
  20#include <asm/mipsregs.h>
  21
  22static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  23        void *data)
  24{
  25        int fpu_owned;
  26        int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  27
  28        switch (action) {
  29        case CU2_EXCEPTION:
  30                preempt_disable();
  31                fpu_owned = __is_fpu_owner();
  32                if (!fr)
  33                        set_c0_status(ST0_CU1 | ST0_CU2);
  34                else
  35                        set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  36                enable_fpu_hazard();
  37                KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  38                if (fr)
  39                        KSTK_STATUS(current) |= ST0_FR;
  40                else
  41                        KSTK_STATUS(current) &= ~ST0_FR;
  42                /* If FPU is owned, we needn't init or restore fp */
  43                if (!fpu_owned) {
  44                        set_thread_flag(TIF_USEDFPU);
  45                        if (!used_math()) {
  46                                _init_fpu(current->thread.fpu.fcr31);
  47                                set_used_math();
  48                        } else
  49                                _restore_fp(current);
  50                }
  51                preempt_enable();
  52
  53                return NOTIFY_STOP;     /* Don't call default notifier */
  54        }
  55
  56        return NOTIFY_OK;               /* Let default notifier send signals */
  57}
  58
  59static int __init loongson_cu2_setup(void)
  60{
  61        return cu2_notifier(loongson_cu2_call, 0);
  62}
  63early_initcall(loongson_cu2_setup);
  64